The typical vehicle headlight has a partially spherical back surface from which extends a pair or more of male terminals which are in turn connected to the vehicle electrical system by a suitable electrical connector. A typical electrical connector consists of a molded plastic socket containing female terminals that grip the male headlight terminals as the socket is plugged to the headlight. The socket must be formed of a material rigid enough to maintain the socket terminals aligned in the proper position to engage the headlight terminals as the socket is plugged to the headlight. The socket will therefor take on an angular orientation relative to the headlight that substantially matches the angle of the headlight terminals. While the headlight terminals are nominally coaxial with the headlight, in practice they are subject to manufacturing tolerances that can vary their angle, and are also subject to bending during shipping and handling. The angle of the socket relative to the headlight will consequently be subject to the same variation. If sealing around the headlight terminal is desired, a separate seal of a less rigid and more conformable material than the socket material must be provided. A seal could be provided by a conventional O ring, which would be compressed by the socket against the back surface of the headlight. However, any compressive force to keep the seal conformed would have to come entirely from the mutual gripping force of the socket and headlight terminals. Consequently, such a seal is impractical with a conventional connector.
Conventionally, the headlight is mounted to the vehicle before the connector is plugged to the headlight. The headlight is generally not mounted to the vehicle by itself, but rather as part of a headlight assembly that includes a front bezel and a rear stamped metal housing. The headlight is first sandwiched between the bezel and the housing to complete the headlight assembly, which can be separately handled more conveniently than the headlight alone. The housing has a partially spherical shape with an inner surface that generally matches the shape of the back surface of the headlight and which is spaced therefrom. The headlight assembly in then mounted to the vehicle by attaching it to the vehicle with adjustable screws that hold the housing up against several vehicle mounted bearing pads. Turning the adjusting screws causes the housing to slide over the pads, thereby aiming the headlight. A hole through the housing gives access to plug the electrical connector socket to the headlight. However, with the headlight assembly already mounted, access to the headlight terminals may be difficult as a practical matter, and plugging the connector to the headlight is not made easier by the strong mutual gripping force necessary between the headlight and socket terminals.
In the conventional headlight assembly, the housing does nothing to positively retain the socket to the headlight. Although the inner surface of the housing overlies the back surface of the headlight, it performs no function as such. Any attempt to use the housing to positively retain the socket to the headlight would be complicated by the fact that the orientation of the socket relative to the housing, spatially and angularly, would vary with the angular variance of the headlight terminals. A designer could not count on a constant relation between the socket and the housing to allow the two to structurally cooperate.